A synergistic promoter suitable for SNCR denitration and application thereof

Abstract

The application provides a synergistic promoter suitable for SNCR denitration and application thereof, the synergistic promoter comprises the following components in parts by weight: 2-80 parts of an activator, the activator is selected from at least one of sodium glycinate, sodium glutamate, sodium iminodiacetate, sodium aspartate, sodium aminopropionate, sodium aspartate and potassium aspartate; 3-12 parts of a catalyst, the catalyst is selected from a soluble heteropoly acid; 1-10 parts of a catalytic aid; the catalytic aid is selected from at least one of a soluble tungstate and a molybdate. A trace amount of the synergistic promoter is added in a commonly used SNCR denitration solution, the reaction speed of NO x with a reducing agent such as ammonia or urea can be accelerated, the temperature window of SNCR reaction is moved downwards, the application range of traditional SNCR technology is expanded, the removal efficiency of NO x is improved, and a low-cost and high-efficiency method is provided for nitrogen oxide pollution treatment in waste gas.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas denitration, and in particular to a synergistic accelerator suitable for SNCR denitration and application thereof. Background Art

[0002] Nitrogen oxides (NO X Nitrogen oxides (NO) are a type of waste gas pollutant composed solely of nitrogen and oxygen, consisting of various compounds. These include N2O, NO, N2O2, N2O3, NO2, N2O4, and N2O5. Nitrogen oxides primarily consist of NO2 and NO. NO accounts for over 95% of nitrogen oxides in the atmosphere, and over 90% of nitrogen oxides in flue gas. Therefore, nitrogen oxide control primarily focuses on reducing NO emissions.

[0003] The concentration of NO in exhaust gas is low, only a few hundred milligrams per cubic meter. x The ultra-low emission concentration standard is less than 50 mg per cubic meter. Because low-concentration NO has weak reactivity, is chemically inert, and is poorly soluble in water, NO pollution control is technically very difficult. Selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) are currently the two most widely used methods for controlling nitrogen oxides. Both utilize a reducing agent containing amine free radicals (usually urea or ammonia solution) to react with nitrogen oxides to produce nitrogen and water, thereby reducing nitrogen oxide emissions. SCR technology is the preferred method for controlling flue gas nitrogen oxides due to its fast reaction speed and high NOx control efficiency. However, this method is complex, requires a large floor space, and is prone to catalyst poisoning and deactivation, resulting in high investment and operating costs. Usually, SNCR technology involves injecting ammonia solution or urea solution at a position where the boiler furnace or flue temperature is appropriate (ammonia solution: 850℃~950℃, urea: 950℃~1050℃) to reduce NO or NO2 in the flue gas to N2 and H2O. Since no catalyst is used, the investment and operating costs are low. The problem is that the reaction speed is slow and the nitrogen oxide treatment efficiency is low, generally only 30%~50%. Increasing the ammonia-nitrogen ratio can improve the nitrogen oxide removal efficiency, but the amount of ammonia escape increases. The escaped ammonia reacts with sulfur trioxide and hydrogen chloride in the flue gas to form ammonium bisulfate and ammonium chloride, which are deposited on the rear heating surface, causing scaling and clogging of the rear heating surface, affecting the equipment life, and reducing the combustion efficiency in the furnace.

[0004] The flue gas temperature of some industrial furnaces is not high. The conventional SNCR technology has low efficiency in nitrogen oxide control and is difficult to meet the increasingly stringent environmental protection requirements. Due to the large-scale use of solar and wind power generation, large coal-fired power plants that play a peaking role need to operate at low loads, and the flue gas temperature is not high. The use of SNCR technology to control NO xPollution, also difficult to meet strict environmental standards. Using SCR technology, catalyst easy deactivation, high cost, heavy burden on enterprises. Therefore, the need to improve the existing selective non-catalytic reduction denitrification technology, reduce cost, improve efficiency, and make the temperature window down, expand the application field of SNCR technology, provide technical support for green development.

[0005] In order to improve the denitrification efficiency of SNCR, broaden the temperature window of SNCR, many scholars have made beneficial exploration. The literature (Chemosphere. 2015, 122: 213-218) proposes that the addition of Na / K ions in the SNCR denitrification liquid can promote the reduction of NH3 to NO in the temperature range of 850~1150℃; The literature (Energy Conversion and Management. 2011, 52(10): 3083-3088) reports that the addition of anion surfactant or / and 1 wt% NaOH mixed additive can improve the efficiency of urea reducing NO in SNCR at 850℃, and make the temperature window of the reaction move to low temperature direction; The literature (Combustion Science and Technology. 2008, (04): 333-337) found that the addition of sodium salt can improve the denitrification efficiency of SNCR, among which the effect of sodium acetate is the most obvious. Although these literatures have achieved some results, the effect is not obvious when the flue gas temperature is lower than 800℃, and the optimal denitrification temperature cannot be moved to low temperature direction. Some patents report the use of solid denitrification agent to improve the removal effect of nitrogen oxides. Patent CN108187490A proposes that the selective non-catalytic reduction denitrification agent is composed of urea, melamine and / or cyanuric acid, active wood powder, bentonite, quicklime, iron red and / or manganese dioxide catalyst; Patent CN106621782A uses urea, ammonium carbonate, ammonium bicarbonate, ammonium acetate, etc. as ammonia source, one or several of polypropylene salt, polyalkyl acrylate, polyacrylamide as synergist, and one or several of stearate, mildew inhibitor, zeolite magnesium oxide and precipitated calcium carbonate as denitrification agent of selective non-catalytic reduction technology, which is used for reducing nitrogen oxides in flue gas at 800~1050℃. The catalyst and catalytic aid in these solid denitrification agents contain solid substances that are insoluble in water or metal salts that generate insoluble hydroxide precipitates in urea and ammonia solution, so they are not suitable for application in SNCR denitrification process of urea or ammonia solution.

[0006] In summary, it is urgent to develop a new type, high efficiency, low cost nitrogen oxides control technology to overcome the problems of high cost of existing SCR technology and low denitrification efficiency, limited temperature window, ammonia escape, limited application of solid denitrification agent of SNCR technology, and meet the environmental protection requirements. SUMMARY

[0007] In view of the above deficiencies of the prior art, the present application aims to provide a synergistic technology suitable for efficient treatment of nitrogen oxides in flue gas, especially boiler flue gas and industrial furnace flue gas, to overcome the defects of the existing SNCR technology, broaden the temperature window of the reaction of the amino reducing agent with NO x , improve the removal efficiency of nitrogen oxides, and reduce the cost of flue gas treatment.

[0008] The amine radicals released by the amino reducing agent (such as urea or ammonia) at high temperatures reduce the nitrogen oxides in the flue gas to nitrogen and water, and the nitrogen oxides oxidize the amine functional groups to nitrogen. Ammonia and NO x The reaction equations are shown in equations (1) and (2):

[0009] 4NH3+4NO+O2→4N2+6H2O (1)

[0010] 2NH3+NO+NO2→2N2+3H2O (2)

[0011] The reaction equations of urea ((NH2)2CO) with NO are shown in equations (3), (4), and (5):

[0012] (NH2)2CO → 2NH2+CO (3)

[0013] NH2+NO → N2+H2O (4)

[0014] 2CO+2NO → N2+2CO2 (5)

[0015] However, the reaction of the amine functional group with NO and NO2 must be carried out at a temperature above 850°C. In order to accelerate the redox reaction rate of nitrogen oxides with the amine functional group, broaden the temperature window of the reaction of the amine functional group with nitrogen oxides, enable SNCR to efficiently treat nitrogen oxide pollution in flue gas, and expand the application field of SNCR technology, the concept of the present application is as follows: a synergistic promoter is developed, a small amount of the synergistic promoter is added to the commonly used SNCR denitration solution, the synergistic promoter has good synergistic denitration effect on the SNCR denitration reducing agent, and the solution containing the synergistic promoter and the amino reducing agent is sprayed into the flue gas, which can effectively broaden the temperature window of the reaction of the amino reducing agent with NO x , improve the removal efficiency of nitrogen oxides. The synergistic promoter of the present application can accelerate the reaction rate of NO x with ammonia or urea and other reducing agents, move the temperature window of the SNCR reaction downward, expand the application range of the traditional SNCR technology, improve the removal efficiency of NO x , and provide a low-cost and high-efficiency method for treatment of nitrogen oxide pollution in waste gas.

[0016] In order to achieve the above-mentioned purposes, the technical solutions of the present application are as follows:

[0017] The present application provides a synergistic promoter suitable for SNCR denitration, comprising the following components by weight:

[0018] 2-80 parts of an activator selected from at least one of sodium glycinate, sodium glutamate, sodium iminodiacetate, sodium aspartate, sodium aminopropionate, sodium aspartate and potassium aspartate.

[0019] 3-12 parts of a catalyst selected from a soluble heteropoly acid.

[0020] 1-10 parts of a catalytic aid selected from at least one of a soluble tungstate and a molybdate.

[0021] That is, the weight ratio of the activator, the catalyst and the catalytic aid in the synergistic promoter is (2-80):(3-12):(1-10), preferably (8-50):(5-10):(2-5).

[0022] As an example, the catalyst is selected from germanium molybdate (H4GeMo 12 O 40 ), germanium tungstate (H4GeW 12 O 40 ), boron molybdate (H5BMo 12 O 40 ), boron tungstate (H5BW 12 O 40 ), cobalt molybdate (H6CoMo 12 O 40 ), cobalt tungstate (H6CoW 12 O 40 ), copper molybdate (H6CuW 12 O 40 ), copper tungstate (H6CuW 12 O 40 ), phosphorus molybdate (H3PMo 12 O 40 ), phosphorus tungstate (H3PW 12 O 40 ), silicon molybdate (H4SiMo 12 O 40 ), silicon tungstate (H4SiW 12 O 40 ), phosphorus molybdate vanadate (H 3+a PMo 12-a V a O 40 , a is a natural number of 1-6), phosphorus tungstate vanadate (H 3+y PW 12-y V y O 40, y = 1 ~ 6 natural number) and phosphomolybdotungstic acid (H3PMo 12−n W n O 40 , n = 0 ~ 12 natural number) at least one.

[0023] As an example, the catalytic aid is selected from at least one of sodium molybdate, potassium molybdate, sodium tungstate, potassium tungstate, ammonium tungstate and ammonium molybdate.

[0024] The application also provides a denitration liquid suitable for selective non-catalytic removal of nitrogen oxides in flue gas, wherein the mass percentage of each component in the denitration liquid is: amino denitration reducing agent 0.5 ~ 50%, activator 0.002 ~ 0.08%, catalyst 0.003 ~ 0.012%, catalytic aid 0.001 ~ 0.01%; the solvent used in the denitration liquid is water.

[0025] As an example, the amino denitration reducing agent is selected from at least one of urea and ammonia.

[0026] Preferably, the mass percentage of the activator in the denitration liquid is 0.008 ~ 0.05%.

[0027] Preferably, the mass percentage of the catalyst in the denitration liquid is 0.005 ~ 0.010%.

[0028] Preferably, the mass percentage of the catalytic aid in the denitration liquid is 0.002 ~ 0.005%.

[0029] Preferably, the mass percentage of the amino denitration reducing agent in the denitration liquid is 1 ~ 30%.

[0030] The application also provides a method for preparing the denitration liquid described above, comprising the following steps: preparing an aqueous solution of the activator, the catalyst, the catalytic aid and the amino denitration reducing agent according to the mass percentage.

[0031] The application also provides the use of the denitration liquid described above, which is contacted with flue gas in a spraying manner at normal pressure, and the nitrogen oxides in the flue gas are removed at a reaction temperature of 550 ~ 900 ℃; wherein the concentration of nitrogen oxides in the flue gas is 80 ppm ~ 1500 ppm, the concentration of SO2 is 0 ~ 2000 ppm and the concentration of O2 is 0 ~ 20 vol%.

[0032] More specifically, the denitration liquid is sprayed into a region with a suitable temperature in the furnace by a liquid delivery system, and reacts with the nitrogen oxides in the flue gas to reduce the nitrogen oxides into nitrogen and water, thereby eliminating the pollution of nitrogen oxides.

[0033] The nitrogen oxide concentration in the flue gas suitable for the denitration liquid is 80 ppm-1500 ppm, the SO2 concentration is 0-2000 ppm, and the O2 concentration is 0-20 vol%.

[0034] The operating pressure is normal pressure, and the optimal reaction temperature range is 560-780 DEG C. Within the optimal range, high denitration rate (> 90%) is ensured, and energy consumption is effectively reduced.

[0035] The present application adds a trace amount of synergistic promoter to the commonly used SNCR denitration solution (including ammonia water, urea and other amine-containing solutions) for selective non-catalytic reduction denitration of boiler and industrial furnace flue gas.

[0036] 1. High denitration efficiency. The composition of the synergistic promoter can be flexibly adjusted according to the changes of flue gas temperature and dust content. Compared with the traditional SNCR denitration technology, the denitration rate is significantly improved, which can reach 99%.

[0037] 2. Large temperature range. The traditional SNCR technology can achieve high NOx removal efficiency at 850 DEG C, but after using the synergistic promoter of the present application, high denitration rate can still be achieved at 550 DEG C, which widens the temperature range of the reaction of NOx with reducing agents such as ammonia or urea, lowers the suitable temperature window, and expands the application range of SNCR technology, so that the flue gas with a temperature lower than 600 DEG C has an economical and applicable denitration technology.

[0038] 3. Simple process. Based on the traditional SNCR technology, a trace amount of synergistic promoter is added to the ammonia water solution or urea solution to achieve high-efficiency denitration in a wide temperature range. Compared with the SCR method, the investment cost is low, no expensive catalyst is used, and the occupied area is small.

[0039] 4. Green process. The added synergistic promoter is completely gasified in the use environment and does not precipitate powder or scale. It has no toxicity, no corrosion, no explosiveness, and no flammability. The catalyst used in the SCR method contains toxic vanadium pentoxide, and there is a problem of waste catalyst treatment. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The figure is a comparison of the denitration effects of the synergistic promoters of example 1 and comparative examples 1-5 in the present application. DETAILED DESCRIPTION

[0041] The present application is further described in conjunction with the examples below, but the content of the present application cannot be limited. Unless otherwise specified, the percentages involved in the examples refer to mass percentages.

[0042] Example 1

[0043] The denitration solution was prepared by mixing the synergistic promoter and urea with water, and the concentration of urea in the denitration solution was 10%. The components of the synergistic promoter and the concentrations of the components in the denitration solution are shown in Table 1. The denitration solution was evaluated in a quartz tube reactor with an inner diameter of 5.4 cm and a height of 100 cm. The gas flow rate was 4500 L / h, and the gas inlet composition was NO: 470 ppm, SO2: 1000 ppm, O2: 9.5 vol%, and the rest was nitrogen. The denitration solution was sprayed into the reactor at a rate of 1000 mL / h using a peristaltic pump. The gas outlet concentration was analyzed online using a Testo 340 flue gas analyzer, and automatic sampling was performed every two minutes. When the operation reached stability, the NO concentration at the gas outlet was measured. The denitration rate was calculated based on the change in the NO concentration, i.e., denitration rate = (inlet NO concentration - outlet NO concentration) / inlet NO concentration x 100%.

[0044] Comparative Examples 1-5 were also prepared by mixing the synergistic promoter and urea with water to form a denitration solution, and the concentration of urea in the denitration solution was 10%. The components of the synergistic promoter and the concentrations of the components in the denitration solution are shown in Table 1. The denitration solution evaluation device and method were the same as in Example 1.

[0045] The results of different synergistic promoters in Example 1 and Comparative Examples 1-5 on promoting the denitration of the reducing agent are shown in Table 2. Figure 1 .

[0046] Table 1

[0047]

[0048] Example 2

[0049] The SNCR synergistic promoter was composed of sodium glycinate, cobalt tungstate, and ammonium molybdate. The denitration solution was prepared by mixing the synergistic promoter and ammonia water with water, and the concentration of ammonia in the denitration solution was 4% (mass), the concentration of the activator sodium glycinate was 0.07% (mass), the concentration of the catalyst cobalt tungstate was 0.008% (mass), and the concentration of the catalytic aid ammonium molybdate was 0.003% (mass).

[0050] The denitration solution evaluation device was the same as in Example 1, the reaction temperature was 610°C, the gas flow rate was 4500 L / h, the gas inlet composition was NO: 530 ppm, SO2: 1600 ppm, O2: 8.7 vol%, and the rest was nitrogen. The denitration solution was sprayed into the reactor at a rate of 1000 mL / h using a peristaltic pump. The gas outlet concentration was analyzed online using a Testo 340 flue gas analyzer, and automatic sampling was performed every two minutes. When the operation reached stability, the NO concentration at the gas outlet was 36-41 ppm.

[0051] Example 3

[0052] The SNCR synergistic promoter is composed of sodium glutamate, phosphotungstic acid (H6PW9V3O 40 ) and sodium molybdate. The denitration liquid is prepared by mixing the synergistic promoter and ammonia water with water, wherein the concentration of ammonia is 4% (mass), the concentration of the activator sodium glutamate is 0.05% (mass), the concentration of the catalyst phosphotungstic acid (H6PW9V3O 40 ) is 0.009% (mass), and the concentration of the catalytic aid ammonium molybdate is 0.004% (mass).

[0053] The denitration liquid evaluation device is the same as that in Example 1, the reaction temperature is 780°C, the gas flow rate is 4500 L / h, the gas inlet composition is NO: 660 ppm, SO2: 1500 ppm, O2: 6.8 vol%, and the rest is nitrogen. The denitration liquid is sprayed into the reactor at a rate of 1000 mL / h by using a peristaltic pump. The gas outlet concentration is analyzed on-line by using a Testo 340 flue gas analyzer, and automatic sampling is performed every two minutes. When the operation reaches stability, the gas outlet NO concentration is 5 ~ 8 ppm.

[0054] Example 4

[0055] The SNCR synergistic promoter is composed of sodium aspartate, germanium molybdate and sodium tungstate. The denitration liquid is prepared by mixing the synergistic promoter and urea with water, wherein the concentration of urea is 10% (mass), the concentration of the activator sodium aspartate is 0.07% (mass), the concentration of the catalyst germanium molybdate is 0.006% (mass), and the concentration of the catalytic aid sodium tungstate is 0.006% (mass).

[0056] The denitration liquid evaluation device is the same as that in Example 1, the temperature is 680°C, the gas flow rate is 4500 L / h, the gas inlet composition is NO: 590 ppm, SO2: 1250 ppm, O2: 9.5 vol%, and the rest is nitrogen. The denitration liquid is sprayed into the reactor at a rate of 1000 mL / h by using a peristaltic pump. The gas outlet concentration is analyzed on-line by using a Testo 340 flue gas analyzer, and automatic sampling is performed every two minutes. When the operation reaches stability, the gas outlet NO concentration is 27 ~ 33 ppm.

[0057] Example 5

[0058] The SNCR synergistic promoter is composed of sodium aspartate, germanium molybdate and sodium tungstate. The denitration liquid is prepared by mixing the synergistic promoter and urea with water, wherein the concentration of urea is 10% (mass), the concentration of the activator sodium aspartate is 0.07% (mass), the concentration of the catalyst germanium molybdate is 0.006% (mass), and the concentration of the catalytic aid sodium tungstate is 0.006% (mass).

[0059] The denitration liquid evaluation device was the same as in Example 1, the temperature was 620°C, the gas flow rate was 4500 L / h, the gas inlet composition was NO: 380 ppm, SO2: 1200 ppm, O2: 9.2 vol%, and the rest was nitrogen. The denitration liquid was sprayed into the reactor at a rate of 1000 mL / h using a peristaltic pump. The gas outlet concentration was analyzed on-line using a Testo 340 flue gas analyzer, and automatic sampling was performed every two minutes. When the operation reached stability, the gas outlet NO concentration was 28 ~ 31 ppm.

[0060] Example 6

[0061] The SNCR synergistic promoter was composed of sodium iminodiacetate, cobalt molybdate, and sodium tungstate. The denitration liquid was prepared by mixing the synergistic promoter and urea with water, and the concentration of urea in the denitration liquid was 10% (mass), the concentration of the activator sodium iminodiacetate was 0.08% (mass), the concentration of the catalyst cobalt molybdate was 0.006% (mass), and the concentration of the catalytic aid sodium tungstate was 0.004% (mass).

[0062] The denitration liquid evaluation was performed in a quartz tube reactor with an inner diameter of 5.4 cm and a height of 100 cm, the reaction temperature was 560°C, the gas flow rate was 4500 L / h, the gas inlet composition was NO: 470 ppm, SO2: 1000 ppm, O2: 9.5 vol%, and the rest was nitrogen. The denitration liquid was sprayed into the reactor at a rate of 1000 mL / h using a peristaltic pump. The gas outlet concentration was analyzed on-line using a Testo 340 flue gas analyzer, and automatic sampling was performed every two minutes. When the operation reached stability, the gas outlet concentration was NO: 45 ~ 48 ppm.

[0063] Example 7

[0064] The evaluation was performed in a power plant fluidized bed boiler, the flue gas amount was 300000 m 3 / h, the flue gas temperature was 600 ~ 650°C, a Gasmet DX4000 flue gas analyzer was used to analyze the flue gas composition, the NO x content in the flue gas was 380 ~ 420 mg / m 3 , the average value was 395 mg / m 3 , the SO2 content was 1200 mg / m 3about 9.8 vol%. The SNCR synergistic promoter is composed of potassium aspartate, germanium-molybdenum acid and sodium tungstate. The denitration liquid is prepared by mixing the synergistic promoter and urea with water. The concentration of urea is 26% (mass), the concentration of the activator potassium aspartate is 0.07% (mass), the concentration of the catalyst germanium-molybdenum acid is 0.007% (mass), and the concentration of the catalytic aid sodium tungstate is 0.006% (mass). The centrifugal pump is used to spray the denitration liquid into the boiler at a rate of 100 L / h, so that the nitrogen oxides in the flue gas react with urea to generate water and nitrogen, and the outlet concentration of nitrogen oxides is maintained at 26-31 mg / m 3 , and the ammonia content is less than 6 mg / m 3 .

[0065] It should be noted that in other embodiments of the present application, other different schemes obtained by specific selection within the range of the steps, components, proportions and process parameters described in the present application can achieve the technical effects described in the present application, so the present application will not list them one by one. For example, when the reducing agent is 0.5%, the activator, catalyst and catalytic aid are at the maximum value, and the synergistic promoter is 0.102%; when the reducing agent is 50%, the activator, catalyst and catalytic aid are at the minimum value, and the synergistic promoter is 0.006% at the minimum. These proportions can widen the temperature window of the reaction between the amino reducing agent and NO x , and improve the efficiency of nitrogen oxide removal.

[0066] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by the person skilled in the art without departing from the spirit and technical thought disclosed in the present application should be covered by the claims of the present application.

Claims

1. A synergistic promoter suitable for SNCR denitration, characterized in that, The synergistic promoter comprises the following components by weight: activating agent 2-80 parts, the activating agent being selected from at least one of sodium glycinate, sodium glutamate, sodium iminodiacetate, sodium aspartate, sodium aminopropionate, sodium aspartate and potassium aspartate; catalyst 3-12 parts, the catalyst being selected from soluble heteropoly acid; catalytic aid 1-10 parts; the catalytic aid being selected from at least one of soluble tungstate and molybdate.

2. The synergistic accelerator according to claim 1, characterized in that, The catalyst is selected from at least one of germanium molybdic acid, germanium tungstic acid, boron molybdic acid, boron tungstic acid, cobalt molybdic acid, cobalt tungstic acid, copper molybdic acid, copper tungstic acid, phosphorus molybdic acid, phosphorus tungstic acid, silicon molybdic acid, silicon tungstic acid, phosphorus molybdovanadic acid, phosphorus tungstovanadic acid and phosphorus molybdotungstic acid.

3. The synergistic accelerator according to claim 1, wherein The catalytic aid is selected from at least one of sodium molybdate, potassium molybdate, sodium tungstate, potassium tungstate, ammonium tungstate and ammonium molybdate.

4. The synergistic accelerator according to claim 1, wherein The weight ratio of the activating agent, the catalyst and the catalytic aid in the synergistic promoter is (8-50):(5-10):(2-5).

5. A denitration liquid suitable for use in the selective non-catalytic removal of nitrogen oxides from flue gas, characterized in that, The denitration liquid comprises the synergistic promoter of any one of claims 1-4 and an amino denitration reducing agent; the mass percentage of each component in the denitration liquid is: amino denitration reducing agent 0.5-50%, activating agent 0.002-0.08%, catalyst 0.003-0.012% and catalytic aid 0.001-0.01%; the solvent used in the denitration liquid is water.

6. The desulfurization solution according to claim 5, characterized in that, The amino denitration reducing agent is selected from at least one of urea and ammonia.

7. The desulfurization solution according to claim 5, characterized in that, The mass percentage of each component in the denitration liquid is: amino denitration reducing agent 0.5-50%, activating agent 0.008-0.05%, catalyst 0.005-0.010% and catalytic aid 0.002-0.005%; the solvent used in the denitration liquid is water.

8. The desulfurization solution according to claim 6, characterized in that, The mass percentage of the amino denitration reducing agent in the denitration liquid is 1-30%.

9. Use of a de-nitrating liquid according to any one of claims 5-8, characterized in that, The denitration liquid is contacted with flue gas in a spraying manner at normal pressure, and the nitrogen oxides in the flue gas are removed at a reaction temperature of 550-900°C; wherein the concentration of the nitrogen oxides in the flue gas is 80 ppm-1500 ppm, the concentration of SO2 is 0-2000 ppm and the concentration of O2 is 0-20 vol%.

10. Use according to claim 9, characterized in that, The reaction temperature is 560-780°C.

Images